ubiquinone-q2 and Phenylketonurias

Low serum ubiquinone-10 concentrations have been described in phenylketonuric patients fed natural-protein-restricted diets. Such low concentrations may be related to increased free radical damage.. We evaluated the relation between low serum ubiquinone-10 concentrations and other lipophilic antioxidants (tocopherol and retinol), selenium, glutathione peroxidase activity, and malondialdehyde concentrations as a marker of lipid peroxidation.. This was a cross-sectional study of 58 patients with phenylketonuria (aged 2-36 y; median: 13 y) under dietary treatment, 58 age-matched control subjects, and 30 children with moderate hyperphenylalaninemia fed unrestricted diets (aged 3-17 y; median: 7.5 y). Serum ubiquinone-10 concentrations were analyzed by HPLC with electrochemical detection. Serum retinol, serum tocopherol, and plasma malondialdehyde were analyzed by HPLC with ultraviolet detection.. A significant positive correlation was observed between ubiquinone-10 and tocopherol (r = 0.510, P < 0.001) in the patients with phenylketonuria. After the patients were stratified into 2 groups according to ubiquinone-10 values, significantly lower concentrations of tocopherol were observed in group 1 (low ubiquinone values) than in group 2 (normal ubiquinone values), the hyperphenylalaninemic children, and the control group. Plasma malondialdehyde concentrations were significantly higher in group 1 than in the other groups. No significant differences between groups 1 and 2 were observed in daily intakes of selenium, ascorbate, tocopherol, or retinol.. Plasma lipid peroxidation seems to be increased in phenylketonuria. Low concentrations of ubiquinone-10 could be associated with either excessive tocopherol consumption or high malondialdehyde concentrations in patients with phenylketonuria.

Topics: Adolescent; Adult; Antioxidants; Case-Control Studies; Child; Child, Preschool; Cross-Sectional Studies; Female; Humans; Lipid Peroxidation; Male; Oxidative Stress; Phenylketonurias; Tocopherols; Ubiquinone

Decreased serum ubiquinone-10 concentrations is a common condition in patients with phenylketonuria (PKU) under dietary treatment. Our aim was to investigate the implication of the metabolic abnormalities of PKU (low concentrations of tyrosine and high concentrations of phenylalanine) and the effect of treatment with phenylalanine-restricted diets in decreased ubiquinone-10 concentrations in PKU patients. We studied 30 PKU patients (age range 5 months to 35 years; median age 7 years) under dietary treatment. Correlation between plasma tyrosine or phenylalanine and serum ubiquinone-10 concentrations was investigated. Daily cholesterol intake was calculated from the data obtained through a dietary questionnaire. The index of dietary control (IDC) was calculated as the average of the medians of plasma phenylalanine concentrations obtained every 6 months in the metabolic control of patients. Negative correlations were observed between serum ubiquinone and the IDC (r=-0.46; p<0.01) in PKU patients. No correlation was observed between tyrosine or daily cholesterol intake and serum ubiquinone concentrations. After adjustment for daily cholesterol intake by multiple linear regression analysis, for each 113 units of increase in IDC values serum ubiquinone decreased 0.1 micromol/L. According to our results, the main factor associated with the decreased serum ubiquinone concentrations was high plasma phenylalanine values. Although daily cholesterol intake seems to be associated with ubiquinone concentrations, it may not be relevant if we take into account the low intake of cholesterol in treated PKU patients.

Topics: Adolescent; Adult; Child; Child, Preschool; Cholesterol; Cholesterol, Dietary; Humans; Infant; Linear Models; Phenylalanine; Phenylketonurias; Tyrosine; Ubiquinone

Ubiquinone-10 is a lipid with important metabolic functions that may be decreased in phenylketonuria (PKU) because patients with PKU consume diets restricted in natural proteins.. We studied serum ubiquinone-10 concentrations in PKU patients.. This was a retrospective, transversal study in which we compared serum ubiquinone-10, plasma cholesterol, plasma tyrosine, and plasma phenylalanine concentrations in 43 PKU patients with concentrations in a reference population (n = 102). Serum ubiquinone-10 concentrations were analyzed by HPLC with ultraviolet detection. Plasma tyrosine and phenylalanine were measured by ion-exchange chromatography.. Serum ubiquinone-10 concentrations in PKU patients were significantly lower than in the reference population (P < 0.01 for patients aged 1 mo to <8 y and P < 0.00005 for patients aged 8-33 y). Moreover, 5 of 18 PKU patients (28%) in the younger age group and 10 of 23 (43%) in the older age group had serum ubiquinone-10 concentrations below the reference interval.. Serum ubiquinone-10 deficiency appears to be related to the restricted diet of PKU patients. Because serum ubiquinone-10 plays a major antioxidant role in the protection of circulating lipoproteins, the correction of ubiquinone-10 concentrations should be considered in PKU patients. Further investigation seems advisable to elucidate whether the deficiency in serum ubiquinone-10 status is clinically significant.

Topics: Adolescent; Adult; Antidotes; Child; Child, Preschool; Cholesterol; Chromatography, High Pressure Liquid; Chromatography, Ion Exchange; Diet; Female; Humans; Infant; Male; Phenylalanine; Phenylketonurias; Reference Values; Retrospective Studies; Tyrosine; Ubiquinone